Expansion reamer



July 12, 1949., W, AUER Em. 2,476,019

EXPANS ION BEAMER Filed 001;. l, 1946 IN VEN TORS William Auer and Pau! E. John BY @fair ATTorney.

Patented July 12, 1949 UNITED 'rares Param* ofi-F1 csf,

.2,476,01@ I 'XiuN'sioN william Auer and rain E. John,` 'ifonsequie N. Y. Application october 1, 1946, serial No. 760,594 s claims. (ci. 'zr-"iti This invention relates to expansion reamers of the kind adapted to be used in a drill press or other machine tool for reaming a hole already bored, to the exact size required.

The object of the invention is the provision of a reamer of this kind which is strong and durable and which is particularly adapted for reaming holes much smaller than can be done by expansion reamers now in use.

Another object of the invention is the provision of a reamer of this kind in which the cutters are formed integrally with the arbor and are adi justable radially thereof.

Still another object of the inventionis the provision of a reamer of this kind adapted forream. ing very small holes and in which the cutters may be accurately adjusted within certain limits? means being provided for indicating the extent of such adjustment. e

A further object is the provision of an im-A proved expansion reamer constructionwhich, although usable in reamers of larger diameter, is especially suitable for reamers of very small die` ameter, and which will permit the reaming of Ia small diameter hole all the way to the bottom of the hole. l

These and other desirable objects are accomplished by the construction disclosed as an illustrative embodiment of the invention in the fol# lowing description and in theA accompanying drawings forming a part hereof, in which:

Fig. 1 is a side elevation of an expansion roamer constructed according to one possible embodiment of the invention;

Fig 2 is a central longitudinal section through the same Fig; 3 is a side elevation of the body with other parts removed;

Fig.y 4 is a fragmentary section showing in de tail devices for retaining the adjusting sleeve in adjusted position Fig. 5i is an endy view of the cutter;

Fig. 6l is a transversey enlarged section taken substantially on the line 6 6 of Fig. 2;

Fig. '7 is a longitudinal section through the ad-4 justing sleeve; showing details of the interior;

Figs. 8,. 9, and 10- are views of a cross pin,V slide block, and taper pin, respectively, which intertwith eachI othen, these three viewsbeing arranged'v to'form a single "exploded" view ofv the construetion;

Fig. 1l is al sidey elevati-on of an'- expansionreamer illustrating another possible embodiment of the invention, parts being sectioned away to expose details ot the construction; and

2 Fig. 12 is a longitudinal section thiough af flffgment of a reamerI showing a modied construction of the forward end.

The same ref er'encenumerals throughout the several views indicate the same parts. Expansion reamers ras heretofore constructed have been incapable o f roam-ing very small open-f ings, and, in the smallest commercially available sizes, have been incapableofreaming all the Way to the bottom of a hole which does-not go entirely through the work piece; The present in-Y vention is intendedespecially for use in small openings, although it is not limited to lsuch use; The expansion reamer ofthe present invention has been used successfully forreaming holes down to 0*.125 of an inch in diameter; and could be used for even smaller holes; downto the neighg borhood of about 0:09391 an inch; -ifdesired5 and the present r eamer will ream all theA way to the bottom of a hole which does not go through the work; Owing to the small sizes of the parts,A they are shown much enlarged and somewhat exagegerated in the drawings, so that the construction maybe more easily understood;

Referring to Figs: 1 to l0 of the drawings, a` preferred form of the reamer is illustrated, com-A prising a main body or reamer ,chuck t3 having a circular cylindrical end or shank adapted to be held in the ohuckof af drill press,` lathe,- or other machine tools' 'Ihe right end of the body, as seen in the drawings; is bored at l5 to form an axial opening therein and thefouter end of said opening is tapered' for receiving the arbor or reaming cutter I1.- The arbor I7 has a central opening extending therethrough longitudinally for the recept-ionv of an expansion' bar inthe form of ataper pin` 2l movable longitudinally therein;

The cutting end ofthe arbor1 is provided with a plurality of radial slots 23 communicating With the central opening therein andy arranged equidis-A tant'ly from each other.y three of the slots are shown,- arraged at sube stantially from' eachother. Adjacent to and intermediate each successive pail f slots 23, th outer Wall of the cutter isr iuted; as seen at 25, thus providing Six cutting' edges on the periphery of the tool, although the exact number of cutters is not an essential part of the inventionf.

It will bie noted cutting edges are thus provided arranged circum# ferentially of the arbor Adjacent its outer' end; the bo'r'e of the arbor' is tapered, as clearly shown at 21' in Fig. 2. The outer end of they taperpinl has a tapered portion 29 which is operable to expand the periph- In the' present instance;

by an inspection of Fig. 5 that and integral therewith;

ery of the cutters when the bar moves longitudinally into engagement with the tapered end of the bore therein. The cutters are expanded radially outward when the tapered end of the expansion bar or taper pin engages the inner inclined walls of the cutters and cams them radially outward to increase the diameter of the operating surface. When the expansion bar is withdrawn the cutters automatically contract due to the resiliency of the material. 'Ihe taper pin 2| is of such length that it does not project beyond the end of the cutter even when the taper pin is moved longitudinally to expand the cutter tor its greatest diameter; hence the cutter may be used to ream a hole all the way to the bottom.

Means are provided for moving the taper pin longitudinally in the arbor to adjust the diameter of the hole being reamed, without the necessity of taking the shank of the reamer out of the chuck in which it is mounted. To this end, the taper pin 2| is threaded at its inner end at 3| to screw tightly into a tapped longitudinal bore in the slide block 33 which has a snug sliding t in the longitudinal bore l5 of the main body. Arranged with a snug sliding fit in a transverse or diametrical bore in the slide block 33 is a cross pin 31 which projects at both ends from the block 33, through milled slots 35 in the main body, into an internal circumferential groove 39 in the wall of the adjusting sleeve 4|. The sleeve 4| is revolvable on the body and is threaded internally at its outer end to engage a helical screw thread 43 on the body adjacent its outer end. Rotation of the sleeve 4| in one direction or the other moves it longitudinally of the body by its engagement with the thread 43, and moves the cross pin 31 by its engagement with its opposite ends, and thus moves the taper pin 2| connected therewith.

Means are also provided for indicating the extent of rotation of the sleeve 4| and consequently the extent of movement of the taper pin and the degree of expansion imparted to the cutters. To thi-s end, the sleeve 4| is beveled at its inner end and graduated to provide a scale 45 adapted to cooperate with a fixed index mark 41 on the L body I3.

In order to prevent accidental rotation of the sleeve 4|, after the parts have been accurately adjusted, means are provided to frictionally engage the sleeve, and retain it in adjusted position. Said means comprises a fine piano wire 49 having one end anchored by extending approximately radially into an opening 50 provided in the body, the remainder of the wire extending along a shallow groove 5| in the body within the sleeve 4|, l this longitudinal part of the wire being slightlyv bent or bowed as seen in Fig. 4 so that it presses outwardly against the inner surface of the adjusting sleeve 4| and thus acts as a frictional detentfor the sleeve. The wire 49 and the groove and opening in which it is mounted are conveniently of a diameter of about 0.020 inch. One end of the groove 5| conveniently serves also as the index mark 41.

The slots or openings 35 which limit the movement of the sleeve, and hence the movement of the taper pin, are preferably formed by milling into the body from diametrically opposite points as shown in Fig. 2, but are of comparatively short length at the center as seen in Fig. 4 of the drawings.

In assembling this reamer, the slide block 33 with the taper pin 2| screwed into it, i-s inserted in the opening l5 in the body, and the sleeve 4| is positioned thereon by a movement from the Ybe manually rotated.

4 inner or upper end of the body to engage the retaining wire 49 and bend it into the groove provided therefor. The sleeve may then be turned until the diametrically opposite openings 53 in the sleeve register with the slots 35 and with the transverse opening in the block 33, whereuponl the pin 31 may be inserted through one of the openings 5| through the slot-s 35 and through the transverse opening in the block 33, thus operatively -connecting the rod 2| with the sleeve 4|. The openings 53 communicate with the internal groove 39 in the sleeve 4| and rotation of the sleeve causes the opposite ends of the pin 31 to enter said groove and retains the pin in the position shown. The externally tapered end of the cutter orarbor |1 is now thrust axially over the pin 29 and is shoved into the tapered opening in the outer end of the main body and is tapped lightly to seat it firmly and nonnrotatably in the main body. This external taper on the cutter (and internal taper in the main body) is preferably at the rate of about 1/4 inch to a foot. The taper 29 at the end of the taper pin 2| is preferably a taper of about 3 degrees, which enables a ne adjustment of the effective diameter of the reamer through a range, for example, of about 0.003 inch in a reamer of a nominal size of 0.125 inch; v Referring now to that embodiment of the invention illustrated in Fig. l1 of the drawings, an expansion reamer is illustrated, having an arbor Si) provided with a longitudinal opening 62 vwhich is threaded at its inner end, as at 64. The outer end of the opening is tapered at 66, and slotted at 68 and grooved or fluted to lform a cutter similar to that previously described. Arranged in the opening in the arbor is an expansion rod or taper pin 1l] tapered at its outer end to cooperate with the tapered inner walls of the cutters at the outer end of said opening. Adjacent itsinner end, the expansion rod i-s threaded to cooperate with the threads 64 on the inner wall of the opening in the arbor, and at its end is provided with a fingerv piece or knob 12 whereby the expansion rod may The finger piece 12 is of a smaller diameter than the arbor so that it does not interfere with the setting of the arbor in a chuck. When the finger piece is turned in Vone direction or the other, the expansion rod is moved in one direction or the other to expand the cutting end of the arbor or to permit it to contract by virtue of its resiliency.

This second embodiment of the invention, like the first embodiment, comprises a simple and" sturdy construction, well adapted to very small expansion reamers of diameters less than those heretofore thought possible. The first embodiment has the advantage reamer may be adjusted without removing the reamer from the chuck of the drill press'or other machine tool. The second embodiment is somewhat simpler and less expensive, but lwhen its diameter is to be adjusted it must be taken out of the chuck in order to obtain access to the adjusting knob 12.

In both embodiments described above, the expansion rod or taper pin has its forward end tapered, and the outer end of the opening through the arbor or cutter is also tapered. It is not necessary to have the arbor opening tapered in all cases, however. better results are frequently secured when the arbor opening is provided with an internal ridgeA or shoulder extending circumferentially around the opening so as to make a definite line-contact that the diameter of theV In fact, evenl 5. with the taper pin. Such a construction is illustrated` in Fig. 12', in whichI a fragment of' the arbor is shown diagrammatically' atf 82, the forward. end thereof being fluted to providev cutting edges as before and being slitted at 841 for easy expansion. The longitudinat bore through the arbor, instead of being tapered at its. forward end, is of cylindrical form with two portions, one of larger diameter as indicated at 85, and the other-of' smaller diameter as indicated at 88, with a ridge or shoulder between them, the shoulder preferably being rounded orin the nature of a bead suchy as shown at. im, extendingcircumferentially around the bore and providing a deli-r nite line-contact engagement with the tapered portion S2 of the taper pin 94.

With this arrangement, amore accurate adjustment of the size of the reamer is` possible. As they taper pin 94 is moved longitudinally in one direction or the other, the contact between the taper pin and the expanding portion or the arbor or cutter is always made at the location of the bead 90, even when the cutter is expanded to its maximum size, and thus the extent of expansion or contraction of the reamer remains substantially a straight line function of the longitudinal movement of the taper pin 94.

This alternative construction of the bore through the arbor or cutter may be used either as a modification of the construction above described in connection with Figs. 1-10 or as a modification of the construction above described in connection with Fig. 11. For many purposes the preferred construction is the one shown in Figs. 1-10 modified, however, by using the shouldered or line-contact form of bore as shown in Fig. 12, rather than the plain taper bore shown in Fig. 2.

It is seen from the foregoing disclosure that the above-mentioned objects of the invention are admirably fulfilled. It is to be understood that the foregoing disclosure is given by way of illustrative example only, rather than by way of limitation, and that without departing from the invention, the details may be varied within the scope of the appended claims.

What is claimed is:

1. An expansion reamer including tubular means having a longitudinally slitted portion near its forward end so that said slitted portion may expand to a larger diameter, a plurality of cutting edges formed integrally on said slitted portion, said slitted portion being internally formed to cooperate with an externally tapered rod, an expansion rod movably mounted within said tubular means and having a tapered portion for cooperation with said formed portion of said tubular means to expand said slitted portion of said tubular means when said expansion rod moves longitudinally in one direction in said tubular means, said tubular means having a portion near its rear end adapted to be encircled by a chuck or the like to turn said tubular means during a reaming operation, and screw threaded means externally accessible at a point between said chuck-encircled portion and said slitted portion for adjusting said expansion rod longitudinally in said tubular means.

2. An expansion reamer as described in claim 1, in which said tubular means includes a slitted tubular member and a separate adapter chuck having a shank adapted to be inserted in a chuck of a machine tool and an opening for receiving the rear end of said tubular member, and in which said screw threaded means includes a sleeve rotatablyy mounted on said adapter chuck in screw threaded engagement therewith, and an operative connection between said sleeve and said expansion rod.

3. An expansion reamer including an adapter chuck having at its rear end a shank adapted to bev mounted' in a chuck -of a machine tool, and having an axial bore with a tapered portion at its forward end, a tubular cutter member havH ing a tapered rear end tting tightly in said tapered portion of said axial bore and having its forward end slitted to provide expansible portions: intern-ally formed to cooperate with a control member, cutting edges formed integrally on said expansible portions, a control rod movable longitudinally in said tubular member, said control rod having near its forward end a tapered portion cooperating with said internal formation oli said expansible portions of said tubular member to varyv the effective diameter of said cutting edges upon axial movement of said control rod, the rear end of said control rod projecting beyond the rear end of said tubular member and into said bore of said adapter chuck, a slide block mounted for longitudinal movement in said bore and operatively connected to said control rod, a sleeve rotatably mounted on said adapter chuck and having screw threaded engagement therewith so that said sleeve is moved axially upon rotation relative to said adapter chuck, and an operative connection between said sleeve and said slide block to move the latter axially in said bore in response to the axial .movements of the former.

4. In an expansion reamer, the combination of a body adapted to have its rear end mounted in a chuck, said body near its forward end being hollow and internally a portion near its rear end externally tapered and adapted to be inserted into and frictionally and detachably secured in the internally tapered part of said body, expansible cutters on said arbor, means on said body for expanding said cutters, said means including a manipulating part externally accessible on said body forwardly of the point where said body is mounted in said chuck, and graduated scale means for indicating the degree of expansion.

5. In an expansion reamer, the combination of a body adapted to be mounted in a chuck, .said body near its forward end being hollow and internally tapered, an arbor having a longitudinal opening therein and having a portion near its rear end externally tapered and adapted to be inserted into and frictionally and detachably secured in the internally tapered part of said body, expansible cutters on said arbor, a rod movable in the opening in said arbor for expanding the cutters, a pin arranged diametrically in said body, projecting therefrom and connected with said rod, a sleeve having an annular groove engaging the ends of said pin, and screw means for moving the sleeve axially to operate said rod.

6. An expansion reamer in accordance with claim 5, further including a longitudinal groove in said body, and a resilient wire arranged in said groove and anchored in said body to resiliently engage the inner wall of the sleeve to retain it in adjusted position.

7. An expansion reamer in accordance with claim 5, further including a groove in said body arranged longitudinally thereof, a resilient wire arranged in said groove and anchored therein to resiliently engage the inner wall of the sleeve to retain it in adjusted position, and a scale on said tapered, an arbor having sleeve cooperating with said groove for indicating the extent of rotation of the sleeve.

8. An expansion reamer including an adapter chuck having at its rear end a shank for mounting in a chuck of a machine tool, and having an axial bore in its forward portion, a tubular cutter member having a rear end iitting tightly in said bore of said adapter chuck and having its forward end slitted to provide expansible portions, cutting edges formed integrally on said expansible portions, a control rod movable longitudinally in said tubular member, said control rod having near its forward end a tapered portion cooperating with the inner surfaces of said expansible portions of said cutter member to vary the effective diameter of said cutting edges upon axial movement of said control rod, the rear end of said control rod projecting beyond the rear end of said tubular cutter member and into said bore of said adapter chuck, a slide block mounted for longitudinal movement in said bore and opera- REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 953,282 Nash Mar. 29, 1910 1,890,052 German Dec. 6, 1932 2,138,897 Anthony Dec. 6, 1938 Frishette Aug. 15, 1944 

